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s390x/pci: Drop release timer and replace it with a flag 

Let's handle it similar to x86 ACPI PCI code and don't use a timer.
Instead, remember if an unplug request is pending and keep it pending
for eternity. (a follow up patch will process the request on
reboot).

We expect that a guest that is up and running, will process the unplug
request and trigger the unplug. This is normal operation, no timer needed.

If the guest does not react, this usually means something in the guest
is going wrong. Simply removing the device after 30 seconds does not
really sound like a good idea. It might sometimes be wanted, but I
consider this rather an "opt-in" decision as it might harm a guest not
prepared for it.

If we ever actually want a "forced/surprise removal", we will have to
implement something on top of the existing "device_del" framework. E.g.
also x86 might want to do a forced/surprise removal of PCI devices under
some conditions. "device_del X, forced=true" could be an option and will
require changes to the hotplug handler infrastructure.

This will then move the responsibility on when to do a forced removal
to a higher level. Doing a forced removal right now over-complicates
things and doesn't really seem to be required.

Let's allow to send multiple requests.

Signed-off-by: David Hildenbrand <david@redhat.com>
Message-Id: <20190130155733.32742-6-david@redhat.com>
Reviewed-by: Collin Walling <walling@linux.ibm.com>
Signed-off-by: Cornelia Huck <cohuck@redhat.com>
This commit is contained in:
David Hildenbrand 2019-01-30 16:57:32 +01:00 committed by Cornelia Huck
parent e0998fe891
commit 9f2a46b111
2 changed files with 8 additions and 33 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

38
hw/s390x/s390-pci-bus.c
View File

@ -194,7 +194,7 @@ void s390_pci_sclp_deconfigure(SCCB *sccb)
pbdev->state = ZPCI_FS_STANDBY;
rc = SCLP_RC_NORMAL_COMPLETION;
if (pbdev->release_timer) {
if (pbdev->unplug_requested) {
s390_pci_perform_unplug(pbdev);
}
}
@ -959,23 +959,6 @@ static void s390_pcihost_plug(HotplugHandler *hotplug_dev, DeviceState *dev,
}
}
static void s390_pcihost_timer_cb(void *opaque)
{
S390PCIBusDevice *pbdev = opaque;
if (pbdev->summary_ind) {
pci_dereg_irqs(pbdev);
}
if (pbdev->iommu->enabled) {
pci_dereg_ioat(pbdev->iommu);
}
pbdev->state = ZPCI_FS_STANDBY;
s390_pci_generate_plug_event(HP_EVENT_CONFIGURED_TO_STBRES,
pbdev->fh, pbdev->fid);
s390_pci_perform_unplug(pbdev);
}
static void s390_pcihost_unplug(HotplugHandler *hotplug_dev, DeviceState *dev,
Error **errp)
{
@ -1002,12 +985,6 @@ static void s390_pcihost_unplug(HotplugHandler *hotplug_dev, DeviceState *dev,
pbdev->state = ZPCI_FS_RESERVED;
} else if (object_dynamic_cast(OBJECT(dev), TYPE_S390_PCI_DEVICE)) {
pbdev = S390_PCI_DEVICE(dev);
if (pbdev->release_timer) {
timer_del(pbdev->release_timer);
timer_free(pbdev->release_timer);
pbdev->release_timer = NULL;
}
pbdev->fid = 0;
QTAILQ_REMOVE(&s->zpci_devs, pbdev, link);
g_hash_table_remove(s->zpci_table, &pbdev->idx);
@ -1054,15 +1031,14 @@ static void s390_pcihost_unplug_request(HotplugHandler *hotplug_dev,
s390_pci_perform_unplug(pbdev);
break;
default:
if (pbdev->release_timer) {
return;
}
/*
* Allow to send multiple requests, e.g. if the guest crashed
* before releasing the device, we would not be able to send
* another request to the same VM (e.g. fresh OS).
*/
pbdev->unplug_requested = true;
s390_pci_generate_plug_event(HP_EVENT_DECONFIGURE_REQUEST,
pbdev->fh, pbdev->fid);
pbdev->release_timer = timer_new_ns(QEMU_CLOCK_VIRTUAL,
s390_pcihost_timer_cb, pbdev);
timer_mod(pbdev->release_timer,
qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL) + HOT_UNPLUG_TIMEOUT);
}
} else {
g_assert_not_reached();

3
hw/s390x/s390-pci-bus.h
View File

@ -35,7 +35,6 @@
#define ZPCI_MAX_UID 0xffff
#define UID_UNDEFINED 0
#define UID_CHECKING_ENABLED 0x01
#define HOT_UNPLUG_TIMEOUT (NANOSECONDS_PER_SECOND * 60 * 5)
#define S390_PCI_HOST_BRIDGE(obj) \
OBJECT_CHECK(S390pciState, (obj), TYPE_S390_PCI_HOST_BRIDGE)
@ -335,8 +334,8 @@ struct S390PCIBusDevice {
MemoryRegion msix_notify_mr;
IndAddr *summary_ind;
IndAddr *indicator;
QEMUTimer *release_timer;
bool pci_unplug_request_processed;
bool unplug_requested;
QTAILQ_ENTRY(S390PCIBusDevice) link;
};